Nonvolatile Memory Programming Order by Channel Hole Diameter
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Solution Overview
Problem
Existing nonvolatile semiconductor memory devices face challenges in programming efficiency due to differences in channel hole diameters, leading to varying program speeds and increased program disturbance among memory cells.
Innovation Solution
A method is introduced where memory cells are programmed based on the size of their corresponding channel holes, with cells having larger diameters programmed first, and the use of a specific program order to minimize program disturbance by controlling the row decoder to apply voltages sequentially from cells farther from the substrate to those closer, reducing the number of program loops required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If memory cells are programmed in arbitrary order, then programming can be completed, but program disturbance increases and programming efficiency decreases
Solution Approach 1:
The patent applies preliminary action by identifying and programming memory cells with larger channel hole diameters first, before programming cells with smaller diameters. This predetermined sequence based on channel hole size characteristics prevents program disturbance to cells that would be sensitive to subsequent programming operations, while maintaining high programming efficiency through systematic ordering.
2Speed
If memory cells with different channel hole diameters are programmed simultaneously, then programming speed is maximized, but program disturbance increases due to varying program speeds
Solution Approach 1:
The patent segments the memory cell population into distinct groups based on channel hole diameter characteristics. By dividing memory cells into segments with similar programming characteristics (larger diameter cells and smaller diameter cells), the patent can program each segment with appropriate timing and voltage conditions, preventing program disturbance while maintaining overall programming speed.
Solution Approach 2:
The patent applies local quality by recognizing that different regions of the memory array have different channel hole diameters and therefore different programming requirements. By tailoring the programming sequence and conditions to the local characteristics of each memory cell group, the patent optimizes both speed and reliability for each local region while maintaining system-wide efficiency.
Data Source
AI summary
A method is provided for programming a nonvolatile memory device, which includes multiple memory cells connected in series in a direction substantially perpendicular to a substrate. The method includes programming a first memory cell of the multiple memory cells, and programming a second memory cell of the multiple memory cells after the first memory cell is programmed, the second memory cell being closer to the substrate than the first memory cell. A diameter of a channel hole of the first memory cell is larger than a diameter of a channel hole of the second memory cell.